The absence of walls eliminates the problems which usually appear during contact between the liquid metal or alloy and these walls. Such contact causes, on the one hand, chemical pollution of the liquid metal from the refractory materials which form the walls and, on the other hand, physical pollution by the formation in their vicinity of dendrides or large sized particles which greatly impair the quality of the metal obtained. The risk of clogging or erosion of the walls are of course also removed. If desired, the directing or the channelling of the liquid streams may be carried out in a controlled atmosphere.
The invention lends itself to numerous applications: batch, semi-continuous or continuous casting, continuous formation of small diameter billets or metal wires, detachment of a liquid stream from the walls which surround it.